I thought you'd all like to see how the gasoline bubbles and boils in my truck, a 1979 Dodge D150 with 318 V-8.

Here is link to Quicktime video..... About 2 megs so it takes a bit to download. How do I edit it to shorter length?

http://members.ll.net/cfield/s6/P7310015.mov

Does anyone know how to cure the problem? It runs out of fuel on heavy throttle and I'm sure it must run lean on the highway this way too.

Good video. How to make it stop? Insulate the hell out of the fuel line on both sides of the fuel pump, reroute lines that pass near heat sources (exhaust manifold...) so that they run well clear of those heat sources. Replace hard metal line with SAE 30R9 flexible fuel injection hose wherever practicable and safe. Where not practicable or safe, delete metal-to-metal retainers and replace them with plastic tie-wraps to avoid direct conduction of heat to the fuel line from the hot engine. Replace the plastic fuel filter with a metal one that has three fittings (the third one is a vapor return line) and route the vapor return back to the fuel tank.

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Too many people who were born on third base actually believe they've hit a triple.

Take a closer look at that video. Notice the lower radiator hose actually touches part of the fuel pump behind the fuel filter. The replacement hose has a different bend than the original and I can't get it to not touch the fuel pump. Know where to get a hose like the original?

Now take a second closer look... notice the duct tape and styrofoam board on the left side of video. I fastened the styro board to the framerail (with duct tape) in an attempt to shield the fuel line (that runs inside the framerail) from exhaust heat. The fuel line from the tank runs inside the right frame rail. The exhaust pipe also runs down the right side.

I prefer to have as little hose as possible in the fuel system. Will it work to slit a hose and put it over the steel line? Side note.... for what ever reason I do not know, the inlet hose to the fuel pump fails every couple years, it cracks and sucks air. I do not know why the inlet hose fails but the outlet hose (under pressure) does not. Strange.

The hard line [from just above the fuel filter to the carburetor] has one vinyl coated support fastened to a fuel pump mount bolt. The other end is screwed into the carburetor needle seat. It is in free air not touching anything between those 2 points.

Yes, I'd like to install the 3-fitting fuel filter but this truck has factory installed dual fuel tanks so this complicates matters. If it did have one tank, how to I get the return line plumbed into the fuel tank?

How about an insulating gasket between the fuel pump and engine block? And insulating washers under the fuel pump attaching bolt heads?

I installed a Delrin spacer between the carb and manifold. I got the dimensions from the original gasket and had the machine shop at work cut it. But I think instead of actually reducing heat buildup in the carb, it sealed a vacuum leak which made the engine run hot. But I could be wrong.

Because...?
Yes but not as well
Still picks up plenty of heat that would be rejected by hose.
Not really. Pick one tank and route the vapor return to it. (If you want a "quick and clean" installation, find out what year trucks used the vapor return system and pick up a fuel gauge sender from that year truck; it'll have the fitting.)
Gotta be careful here; if you space the fuel pump away from the block by more than the pump arm spring preload range, you'll get a knock-knock-knock every time the cam eccentric swings around to actuate the pump (and, I can't recall which engine you have, if there's a pushrod involved it could even drop out of position).

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Too many people who were born on third base actually believe they've hit a triple.

OK, for lack of a sender unit with a dedicated vapor return fitting, can I connect a vapor return line from the 3-port fuel filter to a T inserted into the 1/2" vent hose on the fuel tank? This is the line that goes from the top of the fuel sender to the top of the fill tube. See picture from 1979 Dodge truck FSM.



The senders with factory installed vapor return fitting usually have a hose to put the vapors below the fuel leven in the tank, I guess to condense the vapors. What happens if I don't have that and run the uncondensed vapors into the tank? Will it build up pressure like a steam engine boiler? I imagine some condensation of the vapors will occur in the line between filter in engine compartment and fuel tank. Opinions?

I checked with Chrysler, and find a sender for a 1981 truck is available for $106 list. I don't know yet if it has a vapor return fitting or not. Also on my 1979 truck the sender is fastened to the tank with 6 screws, no lock ring. I don't know which style this 1981 sender for $106 is.